The present invention relates generally to a bulk materials measurement system. More particularly, specific embodiments of the present invention relate to an in-line grain flow measurement device that may be used to control subsequent processing.
In connection with the sale and transfer of products it is often important to accurately measure the amount of the product being sold and transferred. Accurate measurement of products being sold enables a company that manufactured the product to be adequately compensated for their efforts in manufacturing the product. Similarly, accurate measurement of products being transferred enables the transferor to be adequately compensated for the effort associated with transferring the products. Moreover, accurate measurement of product during the transfer of product allows subsequent processing, such a treatment with chemicals to be optimally performed; that is, precise amounts of materials for maximum effectiveness and minimal exposure.
Accordingly, large amounts of products are shipped in bulk such as by placing in a hopper-style railroad car or in a barge. While these shipping methods enable large amounts of product to be transferred, problems are often encountered when the product is transferred to an end user to ensure that the end user obtains a specified amount of product.
To make processing most expedient the weighing, particularly in the context of process controlling, should be done on the material as it is moving. This allows adjustment of operational parameters on a real time or slightly delayed time frame for downstream processes.
Various techniques have been developed to measure the flow of bulk materials. Dougan, U.S. Pat. No. 504,125 and 558,900, each disclose systems for automatically controlling the flow of grain. The Dougan devices each have a plurality of angularly oriented baffles that are aligned perpendicular to the flow of grain. When the force exerted upon the baffles by the grain exceeds a desired level, a gate is activated to slow the flow of grain.
Baker, U.S. Pat. Nos. 771,598 and 932,944, each disclose controlling the flow of grain by allowing the grain to strike a series of angularly oriented plates. As the flow of grain exceeds a specified level, the force of the grain upon the angularly oriented plates causes a door through which the grain passes to be progressively closed.
Harper, U.S. Pat. No. 2,40,315, and Sichet, U.S. Pat. No. 4,729,442, each disclose measuring the flow rate of grain moving along a conveyor. Harper, U.S. Pat. No. 2,872,073, describes a system for measuring and controlling the flow of material from a hopper. The system includes a set of angularly oriented baffles that are aligned horizontally and perpendicular to the flow of material from the hopper. Grain striking the baffles causes the set of baffles to be deflected horizontally and perpendicular to the flow of grain from the hopper and so indicate the material flow rate. When the grain flow rate exceeds a specified level, the baffles engage a piston that is operably connected to a valve that reduces flow of material from the hopper.
Wood, U.S. Pat. No. 4,354,622, discloses a flow control system for controlling and measuring the rate at which material flows from a hopper. A gate valve is provided at a lower end of the hopper to control the flow of material from the hopper. A single angled impact plate is positioned below the hopper so that material passing through the gate valve deflects the impact plate and thereby causes a force that is indicative of the flow rate to be registered by a transducer.
Ohlman, U.S. Pat. No. 5,125,535, discloses measuring the flow of material from a hopper by depositing material upon a rotating disk. A portion of the disk is supported by a scale. Weight of the material on the scale is measured to determine the material flow rate.
Brandt, Jr., U.S. Pat. Nos. 5,230,251 and 5,219,031, each disclose measuring the flow rate of falling objects using an arcuate surface. The arcuate surface causes the downward force to be transformed into horizontal force.
All of the above patents are incorporated herein by reference.
In a preferred embodiment of the invention, a bulk material flow measuring and processing system measures a flow rate for material such as grain along a flow path and provides a control signal based on said flow for controlling a downstream process such as an herbicide applicator. In a preferred embodiment the system includes a grain measuring system, a control portion, a process portion, and a grain conveyance system. The grain measuring system includes a frame, a flow conditioning portion, and a flow measuring portion. The flow measuring portion has a baffle array attached to a lever arm that actuates a load cell upon deflection of the lever arm. The flow conditioning portion has two sets of static deflectors that change the direction of flow twice above the flow measuring portion. The flow conditioning portion is attached to the frame and absorbs the kinetic energy and any pressure head from the grain flow. The conditioning portion may also function as and include a regulating portion that limits the maximum grain flow rate. This may be provided by the limited area between the static deflectors. The output of the load cell may be connected to a control processor that provides a control signal to a process portion that may, for example, control a pump flow rate or a valve to vary the amount of herbicide injected in a seed coating apparatus.
A feature and advantage of the invention is that flow of grain in a diverse range of flow rates may be measured.
A further feature and advantage of the invention is that the flow conditioning is done statically with no moving parts. Moreover, said conditioning is mechanically simple and provides flow rate control as well as controlling the kinematic energy of the falling grain, as well as any pressure associated with a head, that is, the potential energy of a stream of bulk material.
A further feature and advantage of the invention is that the measurement mechanism is mechanically simple and reliable. Moreover the mechanism portion, that is the pivot points and bearings are physically displaced from the flow of the bulk material. This provides a high level of reliability and lessens maintenance. Moreover, the configuration provides a labyrinth seal between the bulk material flow path and the exterior of the system. Although such seal is not air tight it provides excellent containment of the bulk material flow while still providing sufficient freedom of movement of the mechanisms for accurate and reliable operation.
A further feature and advantage of the invention is that the minimal vertical displacement between the conditioning portion and the measurement portion effectively eliminates kinematic and potential energy considerations of the bulk material flow being measured.
A further feature and advantage of the invention is that the flow rate regulation on the bulk material flow is optimally minimal and functions at only an upper limit. Moreover said regulation is done statically with no moving parts.